1. Field of the Invention
The invention relates generally to a method of manufacturing an aluminum oxide film in a semiconductor device. More particularly, the invention relates to a method of manufacturing an aluminum oxide film in a semiconductor device wherein an aluminum oxide film is formed using an atomic layer deposition (ALD) method.
2. Description of the Background
Generally, in the manufacture process of a highly integrated memory devices, aluminum oxide, or Al2O3, has been widely used as a dielectric film of a capacitor and a H2 penetrating device film.
A method of manufacturing an Aluminum oxide film using an ALD method includes alternately spraying an aluminum source and oxygen-containing raw material onto a substrate surface, while keeping the temperature of an aluminum substrate between about 200xc2x0 C. and about 450xc2x0 C. and utilizing a purge process between the raw materials to remove remaining source materials, thus completing deposition of a thin film. Generally, trimethyl aluminum (TMA) is used as the aluminum source, and water vapor is used as the oxygen-containing material. Since water vapor strongly adheres to surrounding materials at temperatures greater than its vaporization temperature, the path along which the water vapor travels must be purged for a long time after the water vapor is supplied to the reactor in order to remove the water vapor, and the delivery line of the water has to be heated. If the water vapor is not completely removed from the path it travels through, e.g., a delivery line, it may react with an aluminum source to form an Aluminum oxide thin film by a parasitic chemical vapor deposition (CVD) method. Therefore, ALD and CVD deposition methods are mixed, so that an irregular thin film is deposited.
In order to overcome the drawback of water vapor as the oxygen-containing raw material, various alcohols are used instead. In this case, however, as the alcohol molecules are significantly larger compared to those of the water vapor, a problem exists in that the growth rate of the thin film per unit cycle during ALD deposition is significantly lowered. Also, when TMA, as the aluminum source, and an alcohol are used, carbon is included in the Aluminum oxide thin film causing an electrical property of the thin film to be degraded.
A method of manufacturing an aluminum oxide film in a semiconductor device includes a first step of substantially simultaneously delivering an aluminum source and an activation gas into a reactor in which a wafer is mounted, via different delivery lines; a second step of removing unreacted aluminum source from the reactor; a third step of substantially simultaneously delivering a reactive alcoholic gas and an activation gas into the reactor via same delivery lines; a fourth step of removing unreacted alcohol from the reactor; and a fifth step of performing a cycle comprising repeating the first step through the fourth step at least one time.